Juan Ramón Jara Martínez (born 6 August 1970 in Asunción) is a retired football defender from Paraguay.
Jara started his career with Olimpia in Paraguay before moving to Argentina to play for clubs such as Rosario Central, Independiente and Colón de Santa Fe. He spent his best years playing for Rosario Central, where he earned than 100 caps, and was part of the team that finished as runners-up in the 1998 Copa CONMEBOL. Jara then returned to Paraguay to play again for Olimpia and then had brief stints at Nueva Chicago (Argentina), Emelec (Ecuador), Nacional and 3 de Febrero (Paraguay) before finally playing for Portuguesa Fútbol Club of Venezuela in 2007.
Jara made his international debut for the Paraguay national football team on 10 June 1993 in a friendly match against Mexico (3-1 loss), substituting Carlos Gamarra in the 75th minute. He obtained a total number of 17 international caps, scoring no goals for the national side.
Jara was part of the Paraguay national football squad that competed at the 1992 Olympic games. Be also participated in a few matches for the 1998 FIFA World Cup qualifiers.
- Torneo República: 1992